Using a Calculator — GCSE Maths Tutorial, Worked Examples & Practice

Revise Using a Calculator (fractions, powers and roots on a calculator, writing full displays and rounding) within Number — Foundation Arithmetic, aligned to Edexcel, AQA & OCR GCSE (9–1) and International GCSE Maths. The interactive practice tool at the top of this page includes 30 self-marking practice questions across 3 structured skill steps, with instant diagnostic feedback and full worked solutions.

Step 1 of 310 interactive practice questions

Fractions, Powers & Full Display

Evaluating multi-step fractions and writing full calculator displays before rounding

Key Method & Revision Notes

On GCSE Calculator papers (Paper 2 & Paper 3), early marks test whether you can enter multi-step fractions, powers, and roots without BIDMAS errors — and write down your full calculator display before rounding.
Golden Exam Habits:
Press the fraction button ($\frac{\square}{\square}$) first so the whole top line is divided by the whole bottom line.
Switching fractions to decimals: On newer calculators (e.g. Casio fx-83GT CW), press EXE (you may need to press FORMAT and scroll to Decimal, or press SHIFT + EXE). On older calculators, press $S \Leftrightarrow D$.
When asked for all the figures on your calculator display, copy every digit before rounding in part (b).

Worked Example

Question:

(a) Work out $\dfrac{23.6 + 2.5^2}{5.3 - 2.1}$. Write down all the figures on your calculator display.

(b) Round your answer to 1 decimal place.

Step-by-Step Solution:

1. Press the fraction key and enter $23.6 + 2.5^2$ on top ($= 29.85$) and $5.3 - 2.1$ underneath ($= 3.2$).

2. Full display: $29.85 \div 3.2 = \mathbf{9.328125}$.

3. Round to 1 d.p.: $9.3$.

$$ \text{(a) } 9.328125 \quad \text{(b) } 9.3 $$

Ready to test this skill? Use the interactive tool at the top of the page to practise 10 self-marking exam-style questions (30 questions loaded in this topic module).

Step 2 of 310 interactive practice questions

Roots, Cubes & Trig Expressions

Evaluating roots, powers and trig functions accurately to a given degree of accuracy

Key Method & Revision Notes

When an expression mixes square roots, cube roots, powers, and trigonometry, check three things on your screen before pressing EXE (or $=$):
Check the cursor leaves the root sign: Press the right arrow ($\rightarrow$) after $\sqrt{19.4}$ before typing $+ 3.2$, otherwise $3.2$ stays trapped inside the root!
Close trig brackets: Type $\sin(42) + 5.1$, not $\sin(42 + 5.1)$. Make sure a small D (Degrees) shows at the top of your screen.
Do not round early: Keep the full unrounded number on screen and round only at the final step.

Worked Example

Question:

Work out $\dfrac{\sqrt{42.5 + 3.8^2}}{2.9 - 1.35}$ correct to 2 decimal places.

Step-by-Step Solution:

1. Numerator $= \sqrt{42.5 + 14.44} = \sqrt{56.94} = 7.545859...$

2. Divide by $1.55$: display shows $4.868296...$

3. Round to 2 d.p.: $4.87$.

$$ 4.87 $$

Ready to test this skill? Use the interactive tool at the top of the page to practise 10 self-marking exam-style questions (30 questions loaded in this topic module).

Step 3 of 310 interactive practice questions

Money, Time & Context Displays

Interpreting calculator decimals as pounds/pence, hours/minutes and whole items

Key Method & Revision Notes

Your calculator gives raw decimals — in worded GCSE questions you must interpret what the display actually means:
Money (£)
Display 18.4 means £18.40 (always 2 d.p. for pounds and pence unless told nearest £).
Time (Hours & Mins)
Display 2.75 hours is not 2 h 75 m! Multiply the decimal by 60: $0.75 \times 60 = 45$ mins $\rightarrow$ 2 h 45 m.
Whole Items / Coaches
Need 4.2 coaches? Round up to 5. Buying tickets with a budget and get 7.8? Round down to 7.

Worked Example

Question:

A coach travels $198\text{ miles}$ at an average speed of $55\text{ mph}$. Write the journey time in hours and minutes.

Step-by-Step Solution:

1. Time $= 198 \div 55 = 3.6$ hours.

2. Whole hours $= 3$. Multiply the decimal by $60$: $0.6 \times 60 = 36$ minutes.

3. Total time: 3 hours 36 minutes.

$$ 3\text{ hours } 36\text{ minutes} $$

Ready to test this skill? Use the interactive tool at the top of the page to practise 10 self-marking exam-style questions (30 questions loaded in this topic module).

Using a Calculator — GCSE Maths Tutorial, Worked Examples & Practice

Fractions, Powers & Full Display

Key Method & Revision Notes

Worked Example

Roots, Cubes & Trig Expressions

Key Method & Revision Notes

Worked Example

Money, Time & Context Displays

Key Method & Revision Notes

Worked Example

Related GCSE Maths Topics (Foundation Arithmetic)